Ancient marine invertebrate species of the Phyla Bryozoa, Molluska, and Porifera have been well established in the oceans for over one billion years. Such organisms have undergone trillions of biosynthetic reactions in their evolutionary chemistry to reach their present level of cellular organization, regulation and defense.
Marine sponges, however, have changed minimally in their physical appearance over the last 500 million years. This suggests a very effective chemical resistance to evolution in response to changing environmental conditions over that period of time. Recognition of the potential for utilizing this biologically potent marine animal for medicinal purposes was recorded in Egypt about 2,700 B.C. and by 200 B.C. sea hare extracts were being used in Greece for their curative effect. This consideration along with the observation that marine animals, e.g., invertebrates and sharks, rarely develop cancer led to the systematic investigation of marine animal and plant anticancer compounds.
By 1968 ample evidence had been obtained, based on the U.S. National Cancer Institute's (NCI) key experimental cancer study systems, that certain marine organisms could provide new and antineoplastic and/or cytotoxic agents and might also lead to compounds which would be effective in the control and/or eradication of viral diseases. Further, these marine organisms were believed to possess potentially useful drug candidates of unprecedented structure which had eluded discovery by other methods of medicinal chemistry. Fortunately, these expectations have been realized, e.g., the discovery of the bryostatins, dolastatins and cephalostatins, many of which are now in preclinical or human clinical studies.
Those researchers presently involved in medicinal chemistry know well the time lag between the isolation of a new compound and its introduction to the market. This procedure takes several years and often takes decades. Accordingly, industry, in association with the U.S. Government, has developed a system of testing criteria which serves two purposes. One is to eliminate those substances which are shown through testing to be economically counterproductive. The second, more important purpose serves to identify those compounds which demonstrate a high likelihood of success and therefore warrant the further study and qualification, and attendant expense, necessary to meet the stringent regulatory requirements which control the ultimate market place.
The current cost to develop this necessary data approaches ten million dollars per compound. Such a large investment will be made only when there is a reasonable opportunity for it to be recovered. Absent such opportunity, there will be no investment and the research involving the discovery of these potentially life saving compounds will cease.
Only two hundred years ago many diseases ravaged mankind. Many of these now have been controlled or eradicated. During the advancement of means to treat or eliminate these diseases, work with appropriate animals was of critical importance.
Current research in the control of cancer in the United States is coordinated by the National Cancer Institute (NCI). To determine whether a substance has anti-cancer properties, the NCI has established a systematic protocol. This protocol, which involves the testing of a substance against a standard cell line panel containing 60 human tumor cell lines, has been verified and has been accepted in scientific circles. The protocol, and the established statistical means for analyzing the results obtained by the standardized testing are fully described in the literature. See: Boyd, Dr. Michael R., Principles & Practice of Oncology, PPO Updates, Volume 3, Number 10, Oct. 1989, for an overview of the testing protocol; Monks et al., "Feasibility of a High-Flux Anticancer Drug Screen Using a Diverse Panel of Cultured Human Tumor Cell Lines", 83 J. Nat. Cancer Inst., No. 11, 757 (1991) and Paull, K. D., "Display and Analysis of Patterns of Differential Activity of Drugs Against Human Tumor Cell Lines; Development of Mean Graph and COMPARE Algorithm", 81 J. Nat. Cancer Inst. Rpts., No. 14, 1088, (1989) for a description of the methods of statistical analysis. Each of these references are incorporated herein by this reference thereto.
Numerous substances have been discovered which demonstrate significant antineoplastic or tumor inhibiting characteristics. As stated above, many of these compounds have been extracted, albeit with great difficulty, from marine animals such as the sponge and sea hare. Once isolation and testing of these compounds has been accomplished, a practical question remains, namely how to produce commercially significant quantities of the desired substance.
Quinine, which is available in practical quantities from the bark of the cinchona plant, differs materially from the compounds which are extracts of marine creatures possessing antineoplastic qualities. The collection and processing of these latter compounds from their natural sources ranges from the grossly impractical to the utterly impossible. Ignoring the ecological impact of such harvesting, the population of these creatures and the cost of collection and extraction make the process unworkable. Artificial synthesis of the active compounds is the only possible solution.
Therefore, the elucidation of the structure of these antineoplastic compounds is essential. After the structure has been determined, a means of synthesis must be determined. This is often a long and arduous procedure because of the idiosyncratic complexity of these naturally occurring, evolutionary modified compounds. In addition, research is necessary to determine whether any portion of the naturally occurring compound is irrelevant to the desired properties, so that focus can be had on the simplest structure having the perceived properties.
The Constitution of the United States (Art. 1, Sec. 8) authorized Congress to establish the United States Patent and Trademark Office (USPTO) to promote scientific progress. In order to obtain patent rights, one must show the utility of the invention. Cancer cell growth in humans often causes pain, suffering, and premature death. The impairment of human cancerous tumor growth is utilitarian in that inhibited cell growth relieves these conditions, thereby allowing the human thus affected to have a longer, more productive life. Little could be more utilitarian than this result.
The recognition of antineoplastic and tumor inhibiting activity as demonstrated by accepted NCI criteria as "utility" can promote research efforts in the United States and is unequivocally essential if those efforts are to obtain even a modest modicum of success.
The sole right obtained from the grant of a Letters Patent is to prevent others from exploiting the subject matter of the patent. This results in the protection of the inventor for a period adequate to allow the recoupment of investment. This in turn provides incentive and the means for further research.